Pour depressants



Patented Feb. 19, 1952 POUR DEPRESSANTS .Louis A. Mikeska, Westfield, N.J., assignor to 'Stan'dardOil Development Company, acorporationof'Delawal-e .No Drawing. Application May 29, 1948, SerialNo. 30,180

4 Claims. (01. 260-609) This invention relates to novel lubricatingcompositions and to the preparation thereof. More particularly,itrelates to the preparation of certain novel products for the purpose,adding such products to lubricating oil compositions to improve theirproperties. The invention further relates to a new methodoflowering ordepressing the pourpoint of waxy mineral lubricating oil.

Many difierent problems are involved in the production of waxy minerallube oils which will pour or flow readilyat low temperatures such asthose encountered in cold climates or even in winter time in warmerclimate. One way of partially solving this problem is to dewax the oil,but this is expensive and in certain respects reduces the quality of theoil. Another method which may either be used alone'or in conjunctionwith a light dewaxing is to add to the waxy lubricant a small amount ofa substance called a'pour depressor which modifies the properties of thewax during crystallization and prevents the growth of the longneedle-like crystals, the interlocking of which is primarily responsiblefor the apparent solidification of the oil. In the use of such pourdepressors, it is known that sometimes a pour depressor will haverelatively good potency in some waxy lubricating oil basestockandrelatively poor potency in other waxy lubricating oil basestock. It .is also known that two or more different pour depressorshaving'relatively the same pour depressor potency as tested by'th'estandard A. S. T. M. pour point test may be quite different in regard totheir pour stability as measured by the procedure described in Oil andGas Journal, June 24, 1943, page 43, using the apparatus labeled Fig. V,or by other tests.

The present invention was based upon the discovery that the potency ofpour-dep'ressorscan be markedly improved by incorporating into the pourdepressor itself prior to the-addition to .the waxy mineral lubricatingoil axsubstanfee which in itself is not an ie'irective p'ou'r depressorbut which acts-to enhance the potency o f-agiven pour -depressor withnoloss-of stability.

It is known-that wax modifyingagentsmay be prepared by condensationofrela-tivelylon'g chain paraffi'nic material such as chlorinatedparafiin wax or olefins corresponding thereto with aromatic hydrocarbonssuch as phenol. The condensation .of such materials has generally beencarried out in the presence of a Friedel-Cra'fts catalyst such asaluminum chloride, boron fluoride, etc preferably .in the presenceof .aninert solvent. This .product is oil soluble and has an average molecularweight above "1000 preferably "from I500 to "5000and.generally has very2 good pour "depressing properties as determined by standard A. S. T. M.pour point tests.

However, under field conditions of winter storage, the oil blends aresubjected to frequent fluctuationsof high and low temperatures. Theseblends have sometimes been found to be solidat temperaturessubstantially above the A. S. T. M. pour point. It is a primary objectof the present invention to modify those Friedel-Crafts condensationproducts in such a way as to either improve their potency, or their pourstability, or both.

Broadly the present invention comprises modifying such wax modifiers andpour depressors which may be referred to as high molecular weightFriedel-Crafts condensation products by directly condensing them furtherwith alpha or beta chloro ethers having an ether linkage which may berepresented by the general formula R-XRHal where R and R representaliphaticradicals, at least one of which contains from 8 to 18 carbonatoms, Hal represents a halogen and X represents a radical selected fromthe class consisting of O-, S and O-CS-'S-. Linkages having oxygen orsulfur as the bridging element have similar characte'ristic's. Thexanthate type ether linkage has the characteristics of both: that is tosay it may be considered as an oxygen linkage or a sulfur linkage or asa combined linkage involving both oxygen and sulfur as bridgingelements.

The invention may be modified byfirst condensing the initial aromaticaliphatic condensation product with formaldehyde in the presence ofhydrogen chloride to obtain a halo-methyb.

phenol and then condensing further with an alkali metal mercaptan. Oneor more groups having the general formula may be introduced into thearomatic nucleus. lows:

Wax phenols can be condensed with a-ChlOl'O- ethers by merely heatingamixture of the two ingredients. When p-chloroalkyl ethers are used asthe modifying agents, Friedel-Crafts type catalysts must be used; Tworeactions may be carried out at temperatures ranging from 10 C. to C.

Complex thioethers and .polyethers and xanthates such as the followingmay be used for the purpose of this reaction:

The basic conditions are as folatsaeoo Phenol or alkylated phenol whencondensed with three or more molecules of chloroalkyl ethers,thioethers, or xanthates yields an effective pour depressant. Thiscondensation generally follows the pattern of the following equation:

If desired the preparation of the stabilized pour depressant may becarried out in the presence of chloroethers or chlorothioethers, thussaving an extra step in its manufacture generally the directcondensation product of ethers or thioethers with wax phenol gives aproduct having greater pour stability and is to be preferred.

The invention will be better understood from a consideration of thefollowing experimental data:

Example 1 93 gms. of wax phenol (0.15 mol based on the hydroxyl group),39.? gms. (=0.15 mol of B- chloroethyl lorol sulfide (C1CH2CH2SC12H25),and 150 cc. of Varsol were placed into a 3-way flask equipped with astirrer and a return condenser. The lorol radical is obtained fromhydrogenated coconut oils and comprises principally the C12 or laurylradical. An alcohol containing principally lauryl alcohol obtained inthis manner is available commercially as Lorol. 10 gms. of aluminumchloride was then added, little by little, over a period of 20 min. Thetemperature of the reaction mixture was then raised to, and maintainedat, TO-75 C. for 2 hours, and then at 90-95" C. for 5 hours. Thereaction mixture was rapidly stirred throughout the time.

On completion of the reaction the product was poured into a mixture ofice and hydrochloric acid, and was extracted with ether. The extract waswashed free of hydrochloric acid and dried over sodium sulfate. Thesolvents and unchanged B-chloroethyl-lorol sulfide were removed byheating in a Claisen flask at 2 mm. and 300 C. bath temperature until nomore product distilled. The residue consisted of 115.4 gms. of darkviscous oil which showed the following pour characteristics when blendedwith paraflin base oil.

4 Example 2.-LauryZthiomethyl-wamphenol Alkylthiomethyl-waxphenols maybe prepared in either of two ways. In both cases the end products havethe same general structure. One may simply condense waxphenol withchloro- -methylalkyl thioether by heating the two ingredients together.But in this case, some side reactions take place which result inconsiderable amount of polymerization or formation of high molecularweight products. Better results can be obtained if the followingprocedure is followed:

To accomplish the desired objective, the reaction is carried out in twosteps. First, the wax phenol is condensed with formaldehyde in thepresence of hydrogen chloride to yield chloromethyl phenol, which is inturn condensed with an alkali metal mercaptide.

Step Number 1-Chloromethyl-waxph enol.-A

3-way flask equipped with a stirrer, a return condenser and an inlettube for hydrogen chloride,

was charged with 42 gms. (1.4 mol) of trioxymethylene, and 300 ml.benzene. Dry hydrogen chloride was then passed through the mixture at 25C. with rapid stirring until saturated. Seventeen grams of hydrogenchloride were absorbed. To this was then added slowly (over a period of20 min.) with stirring and cooling a solution consisting of 295.7 gms.of waxphenol and 300 ml. of benzol. When all the waxphenol had beenadded the temperature was raised to 45-50 C. and maintained at thispoint throughout the reaction time of 4 hours. A slow stream of hydrogenchloride was passed through the mixture continuously.

On completion of the reaction, the mixture was cooled, poured into icewater and extracted with ether. The ether extract was washed severaltimes with ice water and was then dried over sodium sulfate. On removalof the solvent at C. under 2 mm. pressure, a viscous brown residueweighing 310 gms. was obtained. This product may be designated asProduct A. It was found to contain.4.33% organic chlorine.

Step Number z.-'-Laurylthiomethyl-wa.rphenob-A 3-way flask equipped witha stirrer, a return condenser, a thermometer, and a dropping funnel wascharged with 50.5 gms. of lauryl mercaptan and 400 ml. dioxane. To thiswas then added 23.5 gms. of sodium methylate. The dropping funnel wascharged with gms. of chloromethyl waxphenol (Product A above) dissolvedin 150 ml. dioxane. The latter was then added slowly to the reactor withrapid stirring.

The temperature rose spontaneously from 25 to 45 0. As the reactionprogressed, the product in the flask became extremely viscous, hence alittle toluene was added to reduce its viscosity. When all of thechloromethyl derivative had been added, the temperature was raised toresidue which consisted of 1'76 gms. of dark brown viscous liquid, maybe designated as Product B.

'A. S. T. M. pour point data on the product were obtained in theconcentrations indicated,

" in an oil of SAE 10 grade consisting of a mixture of extractedMid-Continent neutral and extracted Mid-Continent Bright Stock. Thisbase assesseoil was also used in all the other examples described below.

In the S. 0. D. Pour Stabilit Test described on page 89, vol. 46, Oiland Gas Journal (1947), the 0.25% blend solidified at F. As the weightof the condensate is 17% greater than that of the original waxphenol,the former has decidedly higher A. S. T. M. potency than the latter.This product too, unlike the unmodified waxphenol, is active not only asa pour depressantbut also "as an anti-oxidant or an anti-corrodant.-

Example '3.-TertiaryoctyZthiomethyZ-wazphenol A highly effective productas a pour depressant and an anti-oxidant was also obtained onsubstitution of tertiary octyl mercaptan for the lauryl mercaptan in amodification of the reaction described in Example 2. In this case, thereaction was carried out in one step as follows:

A 3-way flask equipped with a stirrer, a return condenser and an inlettube for hydrogen chloride, was charged with 108 gms. of waxphenol (0.2mol) 42.3 gms. (0.3 mol) of tertiary octyl mercaptan and 9 gms. (0.3mol) of trioxymethylene. Then, while stirring, hydrogen chloride gas waspassed through the solution at room temperature. The temperature rosespontaneously to 50 C. It was maintained at this point for two hours,and the reaction was finally brought to completion by refluxing for 1hOurS. Hydrogen chloride was passed through the solution throughout thetime.

The mixture was cooled. poured into water, and then extracted withether. The extract was washed and dried over sodium sulfate. On removalof the ether, the residue was topped at 150 C. bath temperature under 2mm. pressure. The reaction product consisted of 122 gms. of dark brownviscous liquid. Its pour depressant. properties were determined in thesame base' oil as was used in the previous examples, andthe tests werecarried out in the concentrations indicated below:

In the s. o. D. Pour Stability test the 0.25% blend solidified at +15 F.

Eaiample 4.-LaurylxanthomethyZ-waxphenol Chloromethyl-waxphenol wasprepared as desired in Step 1 of Example 2. The chlorinated product wasfound to contain 3.84% chlorine.

To prepare the .xanthomethyl derivative 1:. 3- way flask equippedwithastirrenn return condenser, and a thermometer-was chargedwith 500m1. of benzene, .135 (0.2 .mol) of the above describedchloromethyl-waxphencil, and 10.8 gms. of sodium methylate. The mixturewas stirred for awhile =atroom temperature whereupon 41.5.

gms. (0.146 .mol) sodium lauryl .xanthate was added. The mixturewasth-en refluxedro'r four hours withrapidstirring.

:On c001ing,xthe .mixture was poured into-water. acidified with a slight:excess 0f hydrochloricacid, and extracted with ether. The extract waswashed with water and :finally drie'dover-sodium sulfate. .On removal.01 the solvent at C. and 2 mm. pressure a residue weighing 159 gms. andconsisting of a dark brown oil was obtained. Its pour pointcharacteristics were determined in the same oil and in the same way aswas used in the previous examples.

TABLE V Percent 00110. A. S. T. M. Product of Additive Pour Point inBase Oil F.

Base Oil 0 +30 Condensate 0. 25 45 D0. 0. 50 35 Do 1.00 (-35 Originalwaxphenol 0. 25 20 Do 0. 50 --30 Do 1.00 (-35 In the S. O. D. PourStability test the 0.25% blend solidified at +15 F. Here again, as inthe previous examples, though the weight of the modified materialexceeded the weight of the starting product by 18%, the former proved tobe decidedly more active than the latter.

The products obtained as described above were each tested for pourdepressant potency by the Standard A. S. T. M. procedure in a mixture ofextracted Mid-Continent-Neutral and extracted Mid-Continent Bright Stockof SAE 10 grade. The pour point of this base oil blend was +30 F. Thesame base oil was used in all the pour point determinations described.

The products of Example I were stable at -17 F. in the S. O. D. PourStability test described in Oil and Gas Journal, .vol. 46, page 89(1947). It should be noted that although the weight of the condensatewas 25% greater than that of the original phenol, the former has ahigher A. S. T. M. potency than the latter. This means the potency ofthe pour depressant was improved by at least 25%. In addition toimproved potency, the condensates are superior to wax phenols from whichthey are derived in that the former possess antioxidant properties whichare absent in the Wax phenols.

It is not intended that this invention be limited to the specificmaterials which have been mentioned merely forthe sake of illustrationbut only by the appended claims in which it is intended to claim allnovelty inherent in the invention as well as all modifications comingwithin the scope and spirit of the invention.

What I claim is:

1. A process which comprises modifying a Friedel-Crafts condensationproduct of a chlorinated wax and phenol, said condensation producthaving a molecular weight of at least 400, by reacting said condensationproduct with a beta-chloroethyl thioether containing an alkyl grouphaving from 8 to 18 carbon atoms in the:

presence of aluminum chloride.

2. A process according to claim 1 wherein said thioether isbeta-chloroethyl lauryl sulfide.

3. A product having the desirable characteristic of lowering the pourpoint of lubricatin oils with which it is blended which consistsessentially of a Friedel-Crafts condensation product of chlorinated waxand phenol, said condensation product having a molecular weight of atleast 400, which has been modified by reaction with a beta-chloroethylthioether containing an alkyl group having from 8.to 18 carbon atoms inthe presence of aluminum chloride.

4. A product according to claim 3 wherein said thioether isbeta-chloroethyl lauryl sulfide.

LOUIS A. MIKESKA.

. REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,143,142 Dietrich Jan. 10, 19392,201,814 Evans et al May 21, 1940 2,239,515 Bartlett et al. Apr. 22,1941 2,266,737 Bruson et a1 Dec. 23, 1941 2,330,858 Anderson Oct. 5,1943 2,352,435 Hoefielman et a1. June 27, 1944 2,488,134 Mikeska et alNov. 15, 1949

1. A PROCESS WHICH COMPRISES MODIFYING A FRIEDEL-CRARTS CONDENSATIONPRODUCT OF A CHLORINATED WAX AND PHENOL, SAID CONDENSATION PRODUCTHAVING A MOLECULAR WEIGHT OF AT LEAST 400, BY REACTING SAID CONDENSATIONPRODUCT WITH A BETA-CHLOROETHYL THIOETHER CONTAINING AN ALKYL GROUPHAVING FROM 8 TO 18 CARBON ATOMS IN THE PRESENCE OF ALUMINUM CHLORIDE.